/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http.client;

import org.springframework.http.HttpHeaders;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Base implementation of {@link ClientHttpRequest} that buffers output
 * in a byte array before sending it over the wire.
 *
 * @author Arjen Poutsma
 * @since 3.0.6
 */
abstract class AbstractBufferingClientHttpRequest extends AbstractClientHttpRequest {

    private ByteArrayOutputStream bufferedOutput = new ByteArrayOutputStream(1024);


    @Override
    protected OutputStream getBodyInternal(HttpHeaders headers) throws IOException {
        return this.bufferedOutput;
    }

    @Override
    protected ClientHttpResponse executeInternal(HttpHeaders headers) throws IOException {
        byte[] bytes = this.bufferedOutput.toByteArray();
        if (headers.getContentLength() < 0) {
            headers.setContentLength(bytes.length);
        }
        ClientHttpResponse result = executeInternal(headers, bytes);
        this.bufferedOutput = new ByteArrayOutputStream(0);
        return result;
    }

    /**
     * Abstract template method that writes the given headers and content to the HTTP request.
     *
     * @param headers        the HTTP headers
     * @param bufferedOutput the body content
     * @return the response object for the executed request
     */
    protected abstract ClientHttpResponse executeInternal(HttpHeaders headers, byte[] bufferedOutput)
            throws IOException;


}
